My, How the Timelines Change
by SweetSereneShadows
Summary: Why can't you RESET the game while in a battle? Frisk, Chara, and Flowey are about to find out. [Genocide Run meets UnderFell]


The judgement hall. Sure, the monsters didn't know it by that name. But a certain fallen child certainly did.

And they hated the place. Every brick and stone of it.

How many times had the stupid punny skeleton killed them in that hallway? How many times had they had to quickly reset so as not to lose their SOUL?

 _This time… this time for sure. That stupid grin will fade to dust, just like the rest of that smug clown._

A flicker of a new emotion in the child's eyes. The grin falls from their face, and for a second their eye seems like it's about to tear up.

 _please… don't kill him… he's my friend…_

The last remnants of the more innocent of the two. They beg for the skeleton's life, even though it's a hopeless measure. Every time the child spared him, the skeleton took that chance to kill the child.

 _That stupid skeleton? He's killed us so many times, how can you not hate him yet?_

 _you killed all his friends… and his brother… how can't he avenge them?_

 _Me? I didn't do anything, Frisk._ The innocent one's SOUL paled with realization.

 _You killed them. I just sat back and enjoyed the show~._

 _n-no… that's not true… y-you made me k-kill them…_ A laugh from the dominant SOUL.

 _I didn't make you do anything, you did all that yourself. Because you were "curious". Because you were "bored". Because you wanted to see something "new". Because you wanted to see all the endings you could see._

 _st-stop… stop it!_ The grin resurfaced on the child's face as the dominant SOUL began pushing the innocent one back.

 _Sure, I'll stop~. Right after the skeleton dies~._ Powerless, the innocent SOUL could only curl up in the back of the child's mind. Right where it belonged.

* let's just get to the point.

The child nods as they grab their knife.

* it's a beautiful day outside.

The innocent SOUL shivered. The ruthlessness of the dominant SOUL gave off a distinct chill.

* birds are singing, flowers are blooming…

A smirk from the child. The flowers were most certainly dying.

* on days like these, kids like you…

The dominant SOUL glowed brighter for a split second. The thrill of a fight was the only fun it needed.

Bones, lasers, giant skeletal heads… all of them were "been-there, done-that" for the child. Easily dodged.

* here we go.

The child swiped at the skeleton, and as expected they missed. Of course.

* what? you think i'm just gonna stand there and take it?

 _Of course not~! That wouldn't be any fun~!_

More bones, more dodging. Time blurred into itself as the child effortlessly dodged the skeleton's attacks, and the skeleton effortlessly dodged the child's. An outsider would see this as a stalemate, a fight that would go on for eternity. But the child knew better.

All they had to do was wait.

Almost immediately the skeleton began pleading with the child. Perhaps he knew the innocent SOUL was still there, however faintly?

 _Yet when he attacks he's got that same stupid grin on his face… I hate it…_

 _he smiles because he has to… if he frowns you win…_

 _Hah, can't you tell I've already won?_ The innocent SOUL, not having a response to this, curled up again.

It seemed to be only a few seconds before the skeleton began to tire. Sweat somehow beaded all along his bony forehead.

* let's quit fighting.

 _As if! You're not seriously that stupid, are you?_

The innocent SOUL reached out for the skeleton, screaming and crying now.

 _sans! i won't let them hurt you i promise! can't you hear me?!_

 _You brat, don't you remember what happened the last time I let you spare him?_ The innocent SOUL shrank backwards.

 _He will KILL you again. I'm the only one keeping you ALIVE right now._

The child shook as the mental battle went on.

Noticing their own wounds, the child took out a small hamburger from their pocket. That was one of the better qualities of monsters, their ability to infuse magic with food.

Realizing what the dominant SOUL was going to do, the innocent one began begging and pleading incoherently. Disgust flickered in the child's eyes, mirroring the dominant SOUL's.

 _Will you just SHUT UP AND LET ME KILL HIM?!_

The innocent SOUL emitted a whimper-like sound, and it slowly quieted down. Only occasionally did a small whine come from inside it.

Another swipe at the skeleton. This time his face fell as he dodged again. Realizing that the child was watching, he quickly regained his smile. But it was too late. The child saw the slight frown that had begun developing.

 _Not long now~._

* welp, it was worth a shot.

The innocent SOUL twitched. It would have flinched if the dominant SOUL weren't the one in power.

* guess you like doing things the hard way, huh?

The skeleton's attacks came faster now, and before he finished one attack he started another.

* and if you keep pushing me… then i'll be forced to use my special attack.

The child only smirked.

More attacks. Then, suddenly.

* well, here goes nothing… are you ready?

The child patiently waited for his "special attack."

* survive THIS, and i'll show you my special attack!

The child mock-pouted, as if disappointed in the skeleton for not using his special attack.

Being thrown around the room like a ragdoll hardly unnerved the child anymore. If anything, it was almost exhilarating. Perhaps there was a bit of humanity left in the child after all?

The skeleton began panting and wheezing for breath. The child's grin grew.

 _Hehehe~! Shouldn't have wasted your energy on throwing me around~!_

* all right. that's it. it's time for my special attack.

 _please don't hurt him… he's my friend… the only one i have left…_

 _Aw, if he means that much to you, why don't you RESET?_

 _i… i can't… you won't let me…_

 _That's not true~! You're just not strong enough to RESET anymore~!_

* are you ready? here goes nothing.

The child smirked as they stood, immobile. The skeleton had practically given up. Clearly the skeleton was not afraid to stoop to low measures to feel good about himself.

 _that's not true… he's avenging his friends… you KILLED everyone he cared about…_

The innocent SOUL shook with rage.

 _you killed them all… everyone he loved… everyone that made life worth living for him… they're all gone… and you wonder why he's so determined to stop you…_

 _He's determined? I think not. You see, he's already given up. If he really cared about his stupid "friends", he'd keep fighting._

* yep. it's literally nothing. and it's not gonna be anything, either. heh heh heh… ya get it? i know i can't beat you. one of your turns… you're just gonna kill me.

Another whine from the innocent SOUL.

* it's not gonna BE your turn. ever. i'm just gonna keep having MY turn until you give up. even if it means we have to stand here until the end of time. capiche?

The child smiled at the skeleton, and he seemed to understand what that smile meant. Still, he did nothing, no attempt to attack the child.

* you'll get bored here. if you haven't gotten bored already, i mean. and then, you'll finally quit.

Even the innocent SOUL knew that the skeleton was trying to convince himself more than he was trying to convince the dominant SOUL.

After more of the skeleton pleading with himself to believe that the child would give up, he slowly began to fall asleep. The innocent SOUL whimpered, begging for the skeleton to wake up.

As soon as the skeleton was soundly asleep, the child began pushing at the barriers keeping them from fighting. Then, another swipe and…

* heh, didja really think you would be ab-

Before he could finish talking, the child sliced the knife cleanly through the skeleton's shoulder ribcage. The look of shock and terror on his face made the child's stern gaze break into a gleeful smile.

* so… guess that's it, huh?

The innocent SOUL tried in vain to reach out to the skeleton, begging and pleading with the dominant one to RESET the timeline.

* just… don't say i didn't warn you.

The child's smile didn't waver, not for a second. The skeleton sighed, weakly rising to stand.

* welp. i'm going to grillby's.

The shuffle of the skeleton staggering into the shadows seemed to hurt the innocent SOUL further.

* papyrus, do you want anything?

The innocent SOUL let out a squeak, the beginning of a cry, yet there were no tears left. Only the mournful sounds of loss.

The skeleton collapsed to the ground, degrading into a pile of dust. The dominant SOUL laughed triumphantly as they watched their LOVE go up.

 _You see? It wasn't that hard~._

The innocent SOUL seemed to pale slightly, then it grew brighter once more.

 _b-bring my friends back…_

 _Nah. Not done with my fun yet~._

The child admired the pile of dust next to one of the windows before walking across the room and towards the throne room. The grin on their face had grown wider. Nothing could stop them.

 _i-i'm serious chara… bring my f-friends back…_

The innocent SOUL was glowing brighter. Brighter than it had in a long time.

 _You're serious, huh? Well, it's too late for your kind of "serious", Frisk._

The innocent SOUL flickered, then returned to its steady glow.

 _if… if you don't bring my friends back…_

The innocent SOUL's glow became visible through the child's chest, and the tears of the innocent one fell freely now. Taken aback, the dominant SOUL's color wavered for a second.

 _Wh-what are you doing?!_

 _i'm getting my friends back._ Without saying another word, the innocent SOUL drew up all the determination it had left - the few scraps left after the dominant SOUL had forced the innocent SOUL to watch the death of the spaghetti-loving skeleton over and over again. Realization dawned upon the dominant SOUL.

 _N-no! You can't!_

Neither of the SOULS realized that the child's body was still walking. It came upon the great monster king, Asgore. Confusion flooded his eyes as he turned to face the child.

 *** Erm… What kind of monster are you...?**

The child did not answer, the battle between the two SOULs taking prevalence over answering him.

 *** Sorry, I cannot tell.**

The dominant SOUL regained control and pulled the knife out.

 *** Well, we can always-**

Cutting Asgore off, the child lunged forward with the knife.

 *** Now, now. There's no need to fight. Why not settle this…**

.The innocent SOUL regained control and tried to back out of the battle. Then the dominant one stole back command and tightened the hold on the knife.

 *** Over a nice cup of tea?**

One quick swipe was all it took to take the monster king down to his knees. Inside the mind of the child, the innocent SOUL screamed.

 *** Why… You…**

A circle of white bullets surrounded Asgore. Flowey's "friendliness pellets". Two hits from the circle and the king became a pile of pure white dust just like the rest of the monsters. The innocent SOUL began sobbing and begging incoherently once more.

 _Now… where's that little traitor._

As if on cue, Flowey sprang up from the ground in front of the child. His face betrayed his fear almost as much as his voice.

 *** See? I never betrayed you! It was all a trick, see? I was waiting to kill him for you! After all, it's me, your best friend! I'm helpful, I can be useful to you. I promise I won't get in your way.**

The flower's voice began to quaver more.

The innocent SOUL, seeing what the dominant SOUL was planning, screamed as loudly as it could, distracting the dominant one from having control. Knowing that this was its only chance, the innocent SOUL seized back control. Having no voice, the child was restricted to mouthing their warning to Flowey.

 _flowey! run! you've gotta get out of here before chara ki-_

Before the innocent SOUL could finish, the dominant one took back control.

 _Now now, Frisk~! Don't warn the prey, it's so much easier if they don't see it coming~!_

It was too late for the element of surprise. While the innocent one had been in a rush, Flowey had seen the tears in the child's eyes. Though he couldn't discern all the words mouthed, he recognized the ones "chara", "run", and what was probably the beginning of "kill". Strangely, though, the flower elected not to run.

 *** No… I can't run… If I run Chara will still catch me. I… I have to stop them…**

Confusion filled the eyes of the flower as he recognized the glow of a RESET.

 *** Chara? Why… why are you resetting? You're so close to your goal… why reset…?**

 _You stupid goat. I'm not the one resetting!_

The child sneered as their hand slowly reached for the knife. Eight swipes would be all it'd take. However, with the element of surprise lost, Flowey was already prepared to defend himself.

The innocent SOUL panicked as the RESET took longer than it usually did. Something was blocking the process.

A circle of "friendliness pellets" surrounded Flowey, acting as a makeshift shield. It wouldn't hold the child off forever, but it would give him time to come up with a plan.

The innocent SOUL pleaded for the RESET to hurry up and process while the dominant one struggled to bring the knife high enough to stab through Flowey's "friendliness shield".

Finally, at the last second, the RESET began. The knife was almost at the ring of bullets. Flowey's mind raced as he tried to think of a plan.

As the innocent one's SOUL began to glow brighter and brighter, Flowey's panic led him to do something incredibly stupid and reckless. Using his roots as a kind of trampoline, he bounced himself at the child's chest, the source of the glowing. With that, the entirety of the Underground RESET.

Unbeknownst to the three, there was a reason that nobody RESET during a fight. And they were about to learn that very reason.


End file.
